• 대한기계학회논문집A
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• 제24권10호
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• pp.2413-2419
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• 2000

Harmonic resonances in a continuous rotating shaft with distributed mass are discussed. The restoring force of the shaft has geometric stiffening nonlinearity due to the extension of the shaft centerline. The effect of a distributed lateral force, such as the gravity, is assumed. The possibility of the occurrences of harmonic resonances, the shapes of resonance curves, and internal resonance phenomena are investigated.

• 한국공작기계학회논문집
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• 제10권1호
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• pp.43-50
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• 2001

Subharmonic resonances of order 1/2 of a continuous rotating shaft with distributed mass are discussed. The restoring force of the shaft exhibits geometric stiffening nonlinearity due to the extension of the shaft center line. It is assumed that a distributed lateral force, such as the gravity, acts on the rotor. The possibility of the occurrence of subharmonic resonances, the shapes of resonance curves, and internal resonance phenomena are investigate.

• 소음진동
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• 제8권5호
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• pp.908-913
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• 1998

Analogous problem for a gear dynamics where helical gears excite logitudinal forces in the shaft is studied. These shaft forces excite the supporting gear housing through bearing, causing structural vibration. In this study, shaft is modeled as a rod, and bearing is modeled by a massless spring. A simple model for gear housing is a clamped circular plate. To model this force transmission, the transfer functions from the shaft to a clamped circular plate are analytically derived by using the spectral method and four-pole parameter. Finally, radiated noise is computed, using the acoustic relations due to plate surface vibration.

• 한국레이저가공학회지
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• 제5권1호
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• pp.23-31
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• 2002

The uniform metal droplet generation using Nd-YAG laser was studied and experiment was carried out. The shape and volume of developed droplet was measured and the Young-Laplace equation and equilibrium condition of force were applied this model. The differential equation predicting shape of droplet using equilibrium condition of force instead of Navier-stokes equation was induced and numerical solution of differential equation compared with experimentation data. The differential equation was solved by Runge-Kutta method. Surface tension coefficient of droplet was determined with numerical solution relate to experimental result under the statical condition. In case of dynamic vibration, metal droplet shape and detaching critical volume are predicted by recalculating proposed model. The result revealed that this model could reasonably describe the behavior of molten metal droplet on vibration.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.743-748
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• 2007

The important factor to evaluate the running safety of a railway vehicle would be the interaction force between wheel and rail(derailment coefficient), for which is one of important factors to check the running safety of a railway vehicle that may cause a tragic accident. Especially, a newly developed vehicle that first runs commercially requires necessarily the measurement and evaluation of derailment coefficient for securing the safety of a vehicle while measuring the derailment coefficient in view of securing running safety could be the more important factor than any other factors. In this paper, examined possibility that can forecast derailment possibility to behavior of only vibration and displacement by measuring vibration acceleration and displacement in vehicles that travel actuality rail track, and compares with data of wheel load/lateral force result.

• 한국정밀공학회지
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• 제17권9호
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• pp.87-94
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• 2000

In this paper we discuss the control scheme on cooperative control of two flexible manipulators working in 3D space. We propose a control scheme which consists of hybrid position/force control and vibration suppression control. Hybrid position/force control is extended from the scheme for two cooperating rigid manipulators to that for flexible ones. in addition to the control vibration suppression control based upon a lumped-mass-spring model of the flexible manipulators is applied. To illustrate the validity of the proposed control scheme we show experimental results. in the experiment a rigid object is handled by two cooperating flexible manipulators in 3D space.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.28-32
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• 1992

The elimination of chatter vibration is necessary to improve the precision and the productivity of the cutting operation. A new mathematical model of chatter vibration is pressented in order to predict dynamic cutting force from static cutting data. Chatter vibration occurring in the tool structure of lathe is treated theoretically, considering the regenerative effect. The Stability Analysis is carried out by a two degress of freedom system. The dynamic cutting force is analytically expressed by the static cutting coefficient and the dynamic cutting coeccicient which can be determined from the cutting mechanics. The static cutting coefficient controls high speed chatter stability, while the dynamic cutting coefficient dominates low chatter stability. From above considerations, the cirtical width of cut which governs chatter stability was obtained.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.409-414
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• 2011

The drivers of commercial vehicle easily feel tired because of a long time driving and bad road condition. Therefore it is very important to make the driver seat comfortable. This paper introduces the suspension system of driver's seat using magnetic force. The combination of linear spring and magnetic force can make nonlinear spring which has optimal stiffness for minimal vibration transmissibility. The vibrations of driver's seat floor are measured in various road condition. And the numerical simulations and experiments are performed to define the optimal parameter of magnetic suspension system.

• 한국소음진동공학회논문집
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• 제15권9호
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• pp.1045-1052
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• 2005

Tn this paper. dual rotor disk configuration with a coreless stator is proposed for the Lorentz force type integrated motor hearing system. An experimental compensation for the effects of high order harmonics is performed using the digital controller of the experimental setup. The runout profile and rotor unbalance are also identified by the extended influence coefficient method. The experimental results confirm that this compensation scheme effectively attenuates the rotor vibration all over the operating range of rotational speed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1321-1327
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• 2006

This paper presents the calculation of unbalanced magnetic pull (UMP) that causes rotor misalignment in induction motor. The excessive noise and vibration will be occurred by means of rotor misalignment. Angular misalignment of rotor will produce air-gap permeance wave which is function of axial and circumferential coordinate. In this paper, the UMP is calculated using permeance and magneto motive force (MMF) in the case of static and dynamic misalignment. Based on the percentage of misalignment, the result shows that the UMP and magnetic pressure are increased according to the increasing of misalignment. The UMP is occurred not only in It frequency component but also the others.